TonalEnergyTunerMetronome was highly recommended by a friend, he had used it in our vocal rehearsals to give us pitches and tempos. I bought it to try and consolidate all the functions I need in to one app. Initially I found the tuner very jumpy, and I don't like the smiley face with concentric half circles tuning model at all, so I wrote a pretty harsh review. The developer contacted me and pointed out the string tuning mode, which I initially couldn't find because it's not in the tuning section; it's under the sound tab. It makes it much easier to tune my guitar (and it has setting for many stringed instruments from viola to banjo) but if I try to sing long tones or play them on my trumpet, I'm back in the happy face tuner. In theory it should work but to me, the slightest pitch change in a long tone causes the rings to jump erratically. I think that the string mode rescued TonalEnergyTunerMetronome from deletion, and added one star to my rating, but I will still sing and play long tones into the free "pano tuner" rather than deal with the unhappy happy faces. Kudos to the developer for helping me find my way around TonalEnergyTunerMetronome . One more quick gripe, if I'm singing with the metronome playing, TonalEnergyTunerMetronome hears the click and reacts to it, so you essentially can't tune with the metronome on.